bool ValidLogin(Login login)
        {
            UserStore<IdentityUser> userStore = new UserStore<IdentityUser>();
            UserManager<IdentityUser> userManager = new UserManager<IdentityUser>(userStore)
            {
                UserLockoutEnabledByDefault = true,
                DefaultAccountLockoutTimeSpan = new System.TimeSpan(0, 10, 0),
                MaxFailedAccessAttemptsBeforeLockout = 5
            };
            var user = userManager.FindByName(login.UserName);

            if (user == null)
                return false;

            // User is locked out.
            if (userManager.SupportsUserLockout && userManager.IsLockedOut(user.Id))
                return false;

            // Validated user was locked out but now can be reset.
            if (userManager.CheckPassword(user, login.Password)
            && userManager.IsEmailConfirmed(user.Id))
            {
                if (userManager.SupportsUserLockout
                 && userManager.GetAccessFailedCount(user.Id) > 0)
                {
                    userManager.ResetAccessFailedCount(user.Id);
                }
            }
            // Login is invalid so increment failed attempts.
            else
            {
                bool lockoutEnabled = userManager.GetLockoutEnabled(user.Id);
                if (userManager.SupportsUserLockout && userManager.GetLockoutEnabled(user.Id))
                {
                    userManager.AccessFailed(user.Id);
                    return false;
                }
            }
            return true;
        }
        public ActionResult Index(Login login)
        {
            System.Threading.Thread.Sleep(2000); // Add two second delay
            // UserStore and UserManager manages data retreival.
            UserStore<IdentityUser> userStore = new UserStore<IdentityUser>();
            UserManager<IdentityUser> manager = new UserManager<IdentityUser>(userStore);
            IdentityUser identityUser = manager.Find(login.UserName, login.Password);

            if (ModelState.IsValid)
            {
                CaptchaHelper captchaHelper = new CaptchaHelper();
                string captchaResponse = captchaHelper.CheckRecaptcha();
                ViewBag.CaptchaResponse = captchaResponse;

                if (ValidLogin(login) && captchaResponse == VALID_CAPTCHA)
                {
                    IAuthenticationManager authenticationManager
                                           = HttpContext.GetOwinContext().Authentication;
                    authenticationManager
                   .SignOut(DefaultAuthenticationTypes.ExternalCookie);

                    var identity = new ClaimsIdentity(new[] {
                                            new Claim(ClaimTypes.Name, login.UserName),
                                        },
                                        DefaultAuthenticationTypes.ApplicationCookie,
                                        ClaimTypes.Name, ClaimTypes.Role);
                    // SignIn() accepts ClaimsIdentity and issues logged in cookie. 
                    authenticationManager.SignIn(new AuthenticationProperties
                    {
                        IsPersistent = false
                    }, identity);
                    return RedirectToAction("SecureArea", "Home");
                }
            }
            return View();
        }